Model of the mechanism of Ca loss by bones under microgravity and earth conditions

Suvorova, Elena I.; Buffat, PA

doi:10.1002/jbm.10256

Cited by 6 publications

(6 citation statements)

References 15 publications

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“…Two-dimensional nanocrystalline HA may be also synthesized [250]. Space-grown and terrestrial HA crystals were found to differ in size: the former appeared to be at least 1 – 1.5 orders of magnitude bigger in length [251,252]. Transparent HA ceramics can be prepared as well [253,254,255,256].…”

Section: The Members Of the Calcium Orthophosphate Familymentioning

confidence: 99%

Calcium Orthophosphates in Nature, Biology and Medicine

Dorozhkin¹

2009

Materials

692

550

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The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. These materials are of the special significance because they represent the inorganic part of major normal (bones, teeth and dear antlers) and pathological (i.e. those appearing due to various diseases) calcified tissues of mammals. Due to a great chemical similarity with the biological calcified tissues, many calcium orthophosphates possess remarkable biocompatibility and bioactivity. Materials scientists use this property extensively to construct artificial bone grafts that are either entirely made of or only surface-coated with the biologically relevant calcium ortho-phosphates. For example, self-setting hydraulic cements made of calcium orthophosphates are helpful in bone repair, while titanium substitutes covered by a surface layer of calcium orthophosphates are used for hip joint endoprostheses and as tooth substitutes. Porous scaffolds made of calcium orthophosphates are very promising tools for tissue engineering applications. In addition, technical grade calcium orthophosphates are very popular mineral fertilizers. Thus ere calcium orthophosphates are of great significance for humankind and, in this paper, an overview on the current knowledge on this subject is provided.

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Section: The Members Of the Calcium Orthophosphate Familymentioning

confidence: 99%

Calcium Orthophosphates in Nature, Biology and Medicine

Dorozhkin¹

2009

Materials

692

550

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“…To our knowledge these conditions for the sample treatment are optimal and allowed to keep all possible Ca phosphate crystals and to fix an organic part unchanged (Elliot, 1994;Suvorova et al ., 2002;Suvorova et al ., 2004). Both uncoated and gold coated broken bone fragments were characterized by SEM and energy dispersive spectroscopy EDS in a FEI XL30 FEG microscope where the secondary electron SEM images were obtained at 1-10 kV accelerating voltage.…”

Section: Methodsmentioning

confidence: 98%

“…The present work is linked to our previous comprehensive structural investigation of hydroxyapatite (HAP) (Suvorova and Buffat, 2001a;Suvorova and Buffat, 2001b;Suvorova and Buffat, 2002;Suvorova et al ., 2004;Suvorova and Buffat, 2005) precipitated from aqueous solutions under different conditions and formed in living organisms (bones and cardiac valve deposition). A few years ago, a study compared the structure, morphology, and crystal size of Ca phosphate precipitated from aqueous solution and the mineral phase of bones and deposits on cardiac valves using TEM/HRTEM.…”

Section: Introductionmentioning

confidence: 93%

“…A few years ago, a study compared the structure, morphology, and crystal size of Ca phosphate precipitated from aqueous solution and the mineral phase of bones and deposits on cardiac valves using TEM/HRTEM. This study was aimed at modeling possible mechanisms of Ca loss in bones (Suvorova and Buffat, 2002). We suggested that physiological and chemical changes in organisms induced by extreme conditions (microgravity in space, immobilization, etc.)…”

Section: Introductionmentioning

confidence: 99%

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Scanning and Transmission Electron Microscopy for Evaluation of Order/Disorder in Bone Structure

2007

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A comparative characterization of the structure of normal and abnormal (osteoporotic) human lumbar and thoracic vertebrae samples was carried out to reveal the type of possible disorder. Samples from the bone fragments extracted during the surgery due to vertebra fractures were examined by scanning electron microscopy (SEM), conventional and high resolution transmission electron microscopy (TEM and HRTEM), and X-ray energy dispersive spectroscopy (EDS). Contrary to what might be expected in accordance with possible processes of dissolution, formation and remineralization of hard tissues, no changes in phase composition of mineral part, crystal sizes (length, width, and thickness), and arrangement of crystals on collagen fibers were detected in abnormal bones compared to the normal ones. The following sizes were determined by HRTEM for all bone samples:

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“…9-432) and all peaks correspond to the hexagonal crystal form of HAp. 1,10,17,33,[47][48][49][50] From Figure 7, it can be seen that a decreasing degree of crystallinity leads to a decrease in intensity and an increase in width of the diffraction peaks. Moreover, the relative intensity of the peak (300) grows with the increase in the crystallinity degree, which shows that HAp may be oriented along the c-axis.…”

Section: The Fraction Of the Crystalline Phase In Hap Nanoparticlesmentioning

confidence: 99%

Design of experiments (DOE) for the optimization of hydrothermal synthesis of hydroxyapatite nanoparticles

Sadat‐Shojai¹,

Atai²,

Nodehi³

2011

J. Braz. Chem. Soc.

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O objetivo deste trabalho foi investigar a influência de diversos parâmetros de reação sobre as propriedades de nanopartículas de hidroxiapatita (HAp) preparadas pelo método hidrotérmico. Os dados da literatura descrevem condições experimentais variadas para a síntese hidrotérmica de HAp. Uma abordagem específica foi então utilizada para avaliar os fatores estatisticamente influentes entre aqueles descritos na literatura. O papel de cada parâmetro experimental também foi discutido no contexto da nucleação de partículas e do mecanismo de crescimento de cristais. Dentro das variáveis selecionadas, temperatura e pH foram os fatores que mais afetaram a composição e morfologia da HAp. Além disso, neste estudo, diferentes morfologias variando de nanopartículas cilíndricas do tipo bastonete a esféricas com várias características foram obtidas com sucesso, o que pode ser aplicável na preparação de várias biocerâmicas de HAp.The aim of this work was to investigate the influence of different reaction parameters on the properties of hydroxyapatite (HAp) nanoparticles prepared by the hydrothermal method. The literature data describe widely different experimental conditions for the hydrothermal synthesis of HAp. A specific approach was therefore used to evaluate the statistically influential factors among those described in the literature. The role of each experimental parameter was also discussed within the framework of particle nucleation and crystal growth mechanism. Among the selected variables, temperature and pH were found to be the most significant factors affecting the composition and morphology of the HAp. Moreover, in the present study, different morphologies ranging from rod-like to spherical nanoparticles with various characteristics were successfully obtained, which can be applicable for the preparation of various HAp bioceramics.

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Model of the mechanism of Ca loss by bones under microgravity and earth conditions

Cited by 6 publications

References 15 publications

Calcium Orthophosphates in Nature, Biology and Medicine

Calcium Orthophosphates in Nature, Biology and Medicine

Scanning and Transmission Electron Microscopy for Evaluation of Order/Disorder in Bone Structure

Design of experiments (DOE) for the optimization of hydrothermal synthesis of hydroxyapatite nanoparticles

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